/*
 * Copyright 2022 lzhpo
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.lzhpo.sensitive.resolve;

import java.util.Optional;
import javax.servlet.http.HttpServletRequest;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerExecutionChain;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

/**
 * @author lzhpo
 */
@Slf4j
@RequiredArgsConstructor
public class RequestMappingResolver implements HandlerMethodResolver {

  private final RequestMappingHandlerMapping requestMappingHandlerMapping;

  @Override
  public HandlerMethod resolve() {
    return Optional.ofNullable(RequestContextHolder.getRequestAttributes())
        .filter(ServletRequestAttributes.class::isInstance)
        .map(ServletRequestAttributes.class::cast)
        .map(ServletRequestAttributes::getRequest)
        .map(this::getHandler)
        .map(HandlerExecutionChain::getHandler)
        .filter(HandlerMethod.class::isInstance)
        .map(HandlerMethod.class::cast)
        .orElse(null);
  }

  public final HandlerExecutionChain getHandler(HttpServletRequest request) {
    try {
      return requestMappingHandlerMapping.getHandler(request);
    } catch (Exception e) {
      log.error("Cannot get handler from current HttpServletRequest: {}", e.getMessage(), e);
      return null;
    }
  }
}
